Continuous relations and generalized sets
Correction to: Adding a random or a Cohen real: topological consequences and the effect on Martin's axiom
Degrees of non-definability of the Sacks model
Dominating analytic families
Let A be an analytic family of sequences of sets of integers. We show that either A is dominated or it contains a continuum of almost disjoint sequences. From this we obtain a theorem by Shelah that a Suslin c.c.c. forcing adds a Cohen real if it adds an unbounded real.
Embedding Cohen algebras using pcf theory
Using a theorem from pcf theory, we show that for any singular cardinal ν, the product of the Cohen forcing notions on κ, κ < ν, adds a generic for the Cohen forcing notion on .
Examples for Souslin forcing
We give several examples of Souslin forcing notions. For instance, we show that there exists a proper analytical forcing notion without ccc and with no perfect set of incompatible elements, we give an example of a Souslin ccc partial order without the Knaster property, and an example of a totally nonhomogeneous Souslin forcing notion.
Exhaustive zero-convergence structures on Boolean algebras
Existence of non measurable sets
Extensions with the approximation and cover properties have no new large cardinals
If an extension V ⊆ V̅ satisfies the δ approximation and cover properties for classes and V is a class in V̅, then every suitably closed embedding j: V̅ → N̅ in V̅ with critical point above δ restricts to an embedding j ↾ V amenable to the ground model V. In such extensions, therefore, there are no new large cardinals above δ. This result extends work in [Ham01].
Fat P-sets in the Space ω*
We prove that-consistently-in the space ω* there are no P-sets with the ℂ-cc and any two fat P-sets with the ℂ⁺-cc are coabsolute.
Forcing indestructible extensions of almost disjoint families
Forcing with ideals generated by closed sets
Consider the poset where is an arbitrary -ideal -generated by a projective collection of closed sets. Then the extension is given by a single real of an almost minimal degree: every real is Cohen-generic over or .
Games with creatures
Many forcing notions obtained using the creature technology are naturally connected with certain integer games.
Generalized quantifiers in models of set theory
Generic extensions of models of ZFC
The paper contains a self-contained alternative proof of my Theorem in Characterization of generic extensions of models of set theory, Fund. Math. 83 (1973), 35–46, saying that for models of ZFC with same ordinals, the condition implies that is a -C.C. generic extension of .
Goldstern–Judah–Shelah preservation theorem for countable support iterations
[1] T. Bartoszyński, Additivity of measure implies additivity of category, Trans. Amer. Math. Soc. 281 (1984), 209-213. [2] T. Bartoszyński and H. Judah, Measure and Category, in preparation. [3] D. H. Fremlin, Cichoń’s diagram, Publ. Math. Univ. Pierre Marie Curie 66, Sém. Initiation Anal., 1983/84, Exp. 5, 13 pp. [4] M. Goldstern, Tools for your forcing construction, in: Set Theory of the Reals, Conference of Bar-Ilan University, H. Judah (ed.), Israel Math. Conf. Proc. 6, 1992, 307-362. [5] H....
Guessing clubs in the generalized club filter
We present principles for guessing clubs in the generalized club filter on . These principles are shown to be weaker than classical diamond principles but often serve as sufficient substitutes. One application is a new construction of a λ⁺-Suslin-tree using assumptions different from previous constructions. The other application partly solves open problems regarding the cofinality of reflection points for stationary subsets of .
I teoremi di assolutezza in teoria degli insiemi: prima parte
Questa è la prima parte di una articolo espositivo dedicato ai teoremi di assolutezza, un argomento che sta assumendo un’importanza via via più grande in teoria degli insiemi. In questa prima parte vedremo come le questioni di teoria dei numeri non siano influenzate da assunzioni insiemistiche quali l’assioma di scelta o l’ipotesi del continuo.
Internal and forcing models for the impredicative theory of classes [Book]
Iterated ultrapower and Prikry's forcing